Simple Interest
Math MCQs

Question :    Calculate the amount due if Joseph borrowed a sum of $3700 at 10% simple interest for 3 years.

Correct Answer  $4810

Solution & Explanation

Solution

Given,

Principal (P) = $3700

Rate of Simple Interest (SI) = 10%

Time (t) = 3 years

Thus, Amount (A) = ?

The Rate of Interest is always calculated per annum, i.e. per year.

Thus, here 10% simple interest means, Rate of Simple Interest (SI) is 10% per annum.

Method (1) Using Formula

Calculation of Simple Interest

Formula to Calculate Simple Interest

Simple Interest (SI) = Principal × Rate × Time

Thus, Simple Interest (SI) = $3700 × 10% × 3

= $3700 ×¹⁰/₁₀₀ × 3

= ^{3700 × 10 × 3}/₁₀₀

= ^{37000 × 3}/₁₀₀

= ¹¹¹⁰⁰⁰/₁₀₀

= $1110

Thus, Simple Interest = $1110

Calculation of Amount

The total money paid to the lender by a borrower is called the Amount.

In other words, sum of priciple and interest is called the Amount.

Formula to Calculate the Amount

Amount = Principal + Interest

Thus, Amount = $3700 + $1110

= $4810

Thus, Amount to be paid = $4810 Answer

Method (2)

Calculation of Amount when Principal, Rate of Simple Interest and Time are given

Calculation of Amount directly using Principal, SI, and Time

Formula to calculate the Amount

Amount (A) = Principal (P) + Principal(P) × Rate of Interest (SI) × Time (t)

⇒ A = P + PRT

Here in the question, P = $3700

Rate of Simple Interest (SI) or (R) = 10%

And, Time (t) = 3 years

Thus, Amount (A)

= $3700 + ($3700 × 10% × 3)

= $3700 + ($3700 ×¹⁰/₁₀₀ × 3)

= $3700 + (^{3700 × 10 × 3}/₁₀₀)

= $3700 + (^{37000 × 3}/₁₀₀)

= $3700 + (¹¹¹⁰⁰⁰/₁₀₀)

= $3700 + $1110 = $4810

Thus, Amount (A) to be paid = $4810 Answer

Method (3) Unitary Method

Calculation of Amount using Unitary Method

Calculation of Interest using Unitary Method

Here, given Rate of Simple Interest = 10%

This, means, $10 per $100 per year

∵ For $100, the simple interest for 1 year = $10

∴ For $1, the simple interest for 1 year = ¹⁰/₁₀₀

∴ For $3700, the simple interest in 1 year

= ¹⁰/₁₀₀ × 3700

= ^{10 × 3700}/₁₀₀

= ³⁷⁰⁰⁰/₁₀₀ = $370

Thus, simple interest for 1 year = $370

Therefore, simple interest for 3 years

= Simple interest for 1 year × 3

= $370 × 3 = $1110

Thus, Simple Interest (SI) = $1110

Calculation of Amount

Amount = Principal + Interest

Thus, Amount = $3700 + $1110

= $4810

Thus, Amount to be paid = $4810 Answer

Similar Questions

(1) If John paid $3456 to settle his loan which he had taken 4 years before at a simple interest of 2%, then find the loan taken.

(2) Linda took a loan of $4700 at the rate of 10% simple interest per annum. If he paid an amount of $9400 to clear the loan, then find the time period of the loan.

(3) Jessica took a loan of $5500 at the rate of 10% simple interest per annum. If he paid an amount of $9350 to clear the loan, then find the time period of the loan.

(4) What amount will be due after 2 years if Charles borrowed a sum of $3450 at a 6% simple interest?

(5) Sandra took a loan of $6900 at the rate of 6% simple interest per annum. If he paid an amount of $9798 to clear the loan, then find the time period of the loan.

(6) Michael took a loan of $4600 at the rate of 6% simple interest per annum. If he paid an amount of $6532 to clear the loan, then find the time period of the loan.

(7) Thomas had to pay $4256 in order to furnish the loan taken 3 years before. If the rate of simple interest was 4% then find the sum borrowed.

(8) Barbara took a loan of $5100 at the rate of 9% simple interest per annum. If he paid an amount of $9231 to clear the loan, then find the time period of the loan.

(9) Charles took a loan of $5800 at the rate of 7% simple interest per annum. If he paid an amount of $9454 to clear the loan, then find the time period of the loan.

(10) Calculate the amount due if Susan borrowed a sum of $3650 at 10% simple interest for 3 years.